The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the inventors hereof, to the extent the work is described in this background section, as well as aspects of the description that is not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted to be prior art against the present disclosure.
An inductor, which usually takes a form of a coil, is an electrical component that has two terminals and stores electric energy in a magnetic field when an electric current is flowing through it. A radiofrequency (RF) inductor, i.e., an inductor that is built to be operated with an alternating current at a radio frequency, is an important element for radiofrequency oscillators, amplifiers, filters, or the like. At radio frequencies, the inductors have higher resistance and power loss to the circuit, which reduce the Q factor of the circuit.
To maintain a desirable performance of the circuit, RF inductors typically are designed with a larger area, which usually consumes a significant area of the circuit. A metal-only area is usually used to host an inductor on the active area of a circuit, which leads to low area efficiency. Therefore, the current RF circuits suffer from a trade-off between performance and the size of the circuit; i.e., performance of the RF circuit usually needs to be sacrificed in order to achieve a small circuit size, or vice versa.